Expendable Bathythermograph
Expendable Sound Velocimeter
(XBT/XSV)
Expendable Profiling Systems
Expendable Bathythermograph
Expendable Sound Velocimeter
(XBT/XSV)
Lockheed Martin
expendable
profiling systems
offer a fast,
accurate, costeffective means
of collecting
environmental data
without restricting
ship operation.
Launchers
Launchers are
available in three
models. Each is
compatible with ll
XBTs, XSVs and
shipboard data
processing systems.
A standard XBT/XSV system consists of
an expendable probe, a data processing/
recording system, and a launcher.
An electrical connection between the
probe and the processor/ recorder is
made when the canister containing the
probe is placed within the launcher
and the launcher breech door is closed.
Following launch, wire dereels from the
probe as it descends vertically through
the water. Simultaneously, wire dereels
from a spool within the probe canister,
compensating for any movement of the
ship and allowing the probe to freefall
from the sea surface unaffected by ship
motion or sea state.
The XBT/XSV system uses a sea water
ground. As soon as an electrode within
the nose of the expendable probe makes
contact with the water, the circuit is
complete andtemperature or sound
velocity data can be telemetered to the
ship-board data processing equipment.
Data are recorded and displayed in
real time as the probe falls. The nose
of each expendable probe is precision
weighted and the unit spin-stabilized
to assure a predictable rate of descent.
From this rate of descent, probe depth
is determined to an accuracy of +2%.
When the probe reaches its rated
depth (a function of ship speed and
the quantity of wire contained within
the shipboard spool) the profile is
completed and the system is ready for
another launch.
LM-2A
Deck-Mounted
The LM-2A is easily
installed on the deck of any
vessel
XBT and XSV are
available in air-launched
and sub-launched
configurations.
Expendable Bathythermograph
(XBT)
Temperature profiles and computed
sound velocity data obtained by the
XBT are used by ASW operators to
identify the impact of temperature on
sonar propagation and acoustic range
prediction. The XBT also provides
a quick and inexpensive means
of collecting temperature data for
oceanographic and geophysical studies.
The XBT contains a precision
thermistor located in the nose of the
probe. Changes in water temperature are
recorded by changes in the resistance of
the thermistor as the XBT falls through
the water. The XBT is capable of
temperature accuracies of +0.1°C.
The XBT has proved to be reliable in
over 30 years of use. During this time,
Lockheed Martin has developed several
variations of the standard probe to meet
the requirements of a wide range of
applications.
LM-3A Hand-Held
Provides portability, allows
more flexibility in selecting
launcher position and reduces
interference with other equipment.
Expendable Bathythermograph (XBT)
Expendable Sound Velocimeter
(XSV)
Lockheed Martin also offers an XSV
for the direct measurement of sound
velocity. The XSV obtains accurate
sound velocity profiles for the support of
ASW operations, mine countermeasure
operations and oceanographic research.
The XSV measures the speed of sound
in water using a sing around sound
velocity sensor. The XSV obtains real
time sound velocity data accurate to
+0.25 meters/second at depths up to
2000 meters.
The XSV can significantly increase
the accuracy of sonar propagation and
acoustic range predictions, improve
the accuracy of acoustic positioning
systems and provide data for the study
of acoustic propagation in the world’s
oceans. The XSV is most useful in
such areas as Arctic, Mediterranean
and coastal waters where high salinity
variability may cause computed sound
velocity data, based upon temperature
profiles and assumed salinity data, to be
inaccurate.
Expendable Sound Velocimeter (XSV)
XBT provides a quick
and inexpensive means
of collecting temperature
data . . .
XSV obtains accurate
sound velocity profiles . . .
LM-4 Thru-Hull
The standard auncher for all
military vessels. Employs the
same basic assembly as the
LM-2A, however, the LM-4A
is installed below deck for
improved safety and increased
convenience under heavy
weather conditions.
The XBT is capable of temperature
accuracies of +0.1°C.
The XSV obtains real time sound
velocity data accurate to +0.25
meters/second at depths up to
2000 meters.
Lockheed Martin
Mission Systems and Training
300 M. Street, SE
Washington, D.C. 20003
www.lockheedmartin.com/mst/product_contacts
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JUN2013/20050054